Electrophoretic methods, spectrophotometrically determined enzyme characteristics, morphometric features, and metabolite profiles are being investigated for their potential to indicate newly occurring mutational events in mice. The purpose of the work is to seek more effective means to detect germinal mutations while also providing greater understanding of individual mutational effects and of increasing mutation rates generally, on the mammalian organism. The work is directly related with human genetic health risks caused by environmental mutagens. Experimental mutagens which have been used include methylmethane sulfonate, procarbazine, and ethylnitrosourea. A considerable number of spontaneous and induced mutants have been identified. These are being characterized by a variety of criteria.